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European Conference on Optical Communication

High-Rate Continuous-Variables Quantum Key Distribution with Piloted-Disciplined Local Oscillator

Bernhard Schrenk, Fabian Laudenbach, Chi‐Hang Fred Fung, Christoph Pacher, Andreas Poppe, Roland Lieger, D. Hillerkuss, Edwin Querasser, Gerhard Humer, Michael Hentschel, Momtchil Peev, Hannes Hübel

Published Sep 1, 2017• 9 citations
Publisher

Abstract

We present a pilot-disciplined coherent intradyne reception methodology for 250 Mbaud CV-QKD with frequency/phase-matched local oscillator. Experimental measurements indicate a secure key rate of 2.9 Mb/s over a link length of 12.8 km and >30 Mb/s for shorter-reach scenarios.
DOI
10.1109/ecoc.2017.8345964

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In this paper, a high-rate Gaussian-modulated coherent-state (GMCS) continuous-variable quantum key distribution (CV-QKD) scheme with a local local oscillator is experimentally demonstrated. The transmission of quantum signal and pilot tone in optical fiber adopts frequency and polarization multiplexing technology. By optimizing frequency bandwidth, modulation variance and intensity of the pilot tone, the CVQKD system is demonstrated at different metropolitan distance, and the secure key rate of 13.53Mbps, 8.24Mbps, 5.39Mbps 3.66Mbps and 2.55Mbps over transmission distance of 5km, 10km, 15km, 20km and 25km are obtained, respectively.
We report a 100-MHz continuous-variable quantum key distribution (CV-QKD) experiment over a 25-km fiber channel without sending a local oscillator (LO). We use a "locally" generated LO and implement with a 1-GHz shot-noise-limited homodyne detector to achieve high-speed quantum measurement, and we propose a secure phase compensation scheme to maintain a low level of excess noise. These make high-bit-rate CV-QKD significantly simpler for larger transmission distances compared with previous schemes in which both LO and quantum signals are transmitted through the insecure quantum channel.
We propose and demonstrate a fully passive discrete-state continuous-variable quantum key distribution (CV-QKD), which can eliminate all modulator side channels on the source side, using a local local oscillator. Using specially designed phase rotation and discretization methods, the CV-QKD system achieves a maximum fiber transmission length of 100 km at a repetition rate of 1 GHz in asymptotic security, with the corresponding secret key bit rate being 70.7 kbps. In composable security, secret keys are distributed at 25 km of fiber with a secret key bit rate of 1.66 Mbps. Our protocol significantly simplifies the architecture of CV-QKD system by eliminating the need for optical modulators and random number generators as well as presents robust practical security and superior performance, which is comparable to that of its active discrete-state counterpart. Overall, this protocol is expected to play an important role in quantum metropolitan area networks and quantum access networks requiring high realistic security.